In most jurisdictions, your trademark is protected from the date of filing if the trademark ultimately gets registered. From that date, you gain priority over competitors who file or start using your brand elements afterward.
In the US, formal trademark rights begin from the registration date, not the filing date. However, filing does give you a priority date, and common law rights based on commercial use run from the date you first used the mark in commerce.
During the pending period, you can use the ™ symbol to indicate that registration is in progress. Once registered, you can use the ® symbol to signify that your trademark is fully protected.